title: Culture and transfer of human blastocysts increases implantation rates and reduces the need for multiple embryo transfers.
abstract: OBJECTIVE
  To determine whether the transfer of blastocysts on day 5, developed in sequential culture media, resulted in an increase in implantation rate compared with embryos transferred on day 3.
  
  
  METHODS
  Comparative study of embryo culture regimes.
  
  
  METHODS
  Private practice assisted reproductive technology center.
  
  
  METHODS
  Twenty-three patients undergoing routine IVF cycles.
  
  
  METHODS
  Culture of embryos to day 3 in either standard culture conditions or a serum-free chemically defined medium. One hundred one embryos were subsequently cultured from day 3 to day 5 in a second serum-free medium specifically designed to support development of the blastocyst.
  
  
  METHODS
  Embryo cell number and quality on day 3. Blastocyst development on day 5. Implantation rate (determined by fetal heart) and ongoing pregnancy rate (PR).
  
  
  RESULTS
  Implantation rates for embryos transferred at the blastocyst stage of development were twice that observed for embryos transferred on day 3, around the eight-cell stage. Significantly more embryos were required for transfer on day 3, compared with day 5, to establish similar PRs.
  
  
  CONCLUSIONS
  Viable human blastocysts can be obtained in sequential culture media in the absence of coculture and serum. Transfer of blastocysts in IVF will facilitate high PRs while limiting the number of embryos transferred and therefore minimizes the risk of multiple gestation.
authors.affiliation: Institute of Reproduction and Development, Monash Medical Centre, Monash University, Melbourne, Victoria, Australia.
authors.forename: D K
authors.initials: DK
authors.lastname: Gardner
authors.forename: P
authors.initials: P
authors.lastname: Vella
authors.forename: M
authors.initials: M
authors.lastname: Lane
authors.forename: L
authors.initials: L
authors.lastname: Wagley
authors.forename: T
authors.initials: T
authors.lastname: Schlenker
authors.forename: W B
authors.initials: WB
authors.lastname: Schoolcraft
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000502:physiology; D002452:Cell Count; D046508:Culture Techniques; D010064:Embryo Implantation; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000166:cytology / Q000502:physiology; D005260:Female; D006801:Humans; D011247:Pregnancy; D018873:Pregnancy Rate; D019233:Retreatment; D013997:Time Factors